The Melanoma Clinical Cooperative Group, comprised of Harvard University, Temple University, New York University, and the University of California at San Francisco, has been working to study the natural history of malignant melanoma. At each institution, standardized forms have been filled out on clinical parameters, histopathology, and follow-up. These forms are stored, computerized and analyzed at the Massachusetts General Hospital, the coordinating center, The goals of the project include refinement of clinical diagnosis, especially detection of early primary melanomas of the skin; educational programs related to clinical diagnosis; evaluation and refinement of clinicopathologic classification; immunologic status of patients; determination and therapy of patients with a high risk neoplasm; determination of the relationship of sunlight to anatomic distribution of melanoma. To date 802 cases of primary malignant melanoma have been entered by the groups in a four-year period. Studies involving histopathological leveling, urinary melanogens, and serum tyrosinase are in the preliminary stages. Studies involving the relationship of sunlight and melanoma and increased splenic uptake in melanoma patients on scanning are being readied for publication. An adjuvant therapy protocol involving transfer factor has been developed for patients with high risk primary cutaneous malignant melanoma.